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Sequential depolarization of root cortical and stelar cells induced by an acute salt shock - implications for Na+ and K+ transport into xylem vessels

Citation

Wegner, LH and Stefano, G and Shabala, L and Rossi, M and Mancuso, S and Shabala, S, Sequential depolarization of root cortical and stelar cells induced by an acute salt shock - implications for Na+ and K+ transport into xylem vessels, Plant, Cell and Environment, 34, (5) pp. 859-869. ISSN 0140-7791 (2011) [Refereed Article]


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Copyright Statement

2011 Blackwell Publishing Ltd The definitive published version is available online at: http://onlinelibrary.wiley.com/

DOI: doi:10.1111/j.1365-3040.2011.02291.x

Abstract

Early events in NaCl-induced root ion and water transport were investigated in maize (Zeamays L) roots using a range of microelectrode and imaging techniques. Addition of 100 mM NaCl to the bath resulted in an exponential drop in root xylem pressure, rapid depolarization of trans-root potential and a transient drop in xylem K+ activity (AK+) within ~1 min after stress onset. At this time, no detectable amounts of Na+ were released into the xylem vessels. The observed drop in AK+ was unexpected, given the fact that application of the physiologically relevant concentrations of Na+ to isolated stele has caused rapid plasma membrane depolarization and a subsequent K+ efflux from the stelar tissues. This controversy was explained by the difference in kinetics of NaCl-induced depolarization between cortical and stelar cells. As root cortical cells are first to be depolarized and lose K+ to the environment, this is associated with some K+ shift from the stelar symplast to the cortex, resulting in K+ being transiently removed from the xylem. Once Na+ is loaded into the xylem (between 1 and 5 min of root exposure to NaCl), stelar cells become more depolarized, and a gradual recovery in AK+ occurs.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Plant Biology
Research Field:Plant Physiology
Objective Division:Plant Production and Plant Primary Products
Objective Group:Summer Grains and Oilseeds
Objective Field:Summer Grains and Oilseeds not elsewhere classified
Author:Shabala, L (Dr Lana Shabala)
Author:Shabala, S (Professor Sergey Shabala)
ID Code:72227
Year Published:2011
Web of Science® Times Cited:23
Deposited By:Agricultural Science
Deposited On:2011-08-24
Last Modified:2012-05-17
Downloads:0

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